On Wed, 18 Feb 2015 18:30:09 +0000 Dmitry O Litvintsev <litvinse@xxxxxxxx> wrote: > > Yes, deadlock occurs when there are multiple processes insert > concurrently into file table with the same volume id field. > I used "sometimes" as opposed to "all the time". I resonded in that way since I frequently hear people complaining, "we're seeing all kinds of deadlocks" as if the whole world is collapsing under the deadlocks, but when pressed for more information it turns out they're only seeing a few deadlocks per hour when the system is under the heaviest load -- that scenario is hardly unexpected. As a result, having more detailed information than just "sometimes" helps to understand what's really going on. > I think you advise to retry transaction or add select for update prior > to insert. I will pursue this (together with upgrade to 9.3.6 suggested by > Alvaro). The nice thing about a retry strategy is that it always works. The problem with a retry strategy is that it's easy to do wrong (i.e. it may be more than just the transaction that needs to restart ... depending on what data has changed, calculations may need to be redone, the user requeried for certain information, etc). The problem with the SELECT ... FOR UPDATE is that it's a bit slower, and can be significantly slower unders some circumstances, but it's easier to implement correctly. The good news form Alvaro is that this is probably happening more frequently than necessary because of the bug he mentioned ... so upgrading may cause the problem to happen infrequently enough that you don't really care about it. The solutions I suggest are still relevent, they just might not be as immediately important. -- Bill Moran -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
